The Heathrow Connect service runs every half-hour throughout the day and evening from Monday to Saturday and every hour on Sunday. It follows the same route as the Heathrow Express service, but while Heathrow Express runs non-stop between Paddington and the airport, Heathrow Connect stops at some stations in between. Altogether, there are eight stations at which Heathrow Connect trains stop, so the train can connect places in west London with each other, the airport, and Central London. The trains used on the line are five Class 360s made by Siemens.

On 20 May 2018 TfL Rail took over operation of the Heathrow Connect service.